The biting incidents have forced the shutdown of a number of parks and outdoor programs across the city.

"Obviously, they don't want to be found, and they are very, very agile and they have shown to be aggressive," Chris Alexander, who works for the City of Markham, said of the canines.

Until the animals are found and taken out of the area, the city has cancelled recreational programs and closed parks in the following locations:

Huntington Park

Bayview Reservoir

Thornlea Secondary School

Thornlea East Park

Green Lane Park

Bishops Cross Park

St. Roberts Field

Duncan Park

Bayview Fairway

The city says it will reassess on Thursday, depending on whether there are sightings of the dogs.

Residents in any wooded or ravine areas in the territory bordered by Highway 407, John Street, Bayview Avenue and Highway 404 are strongly urged to exercise caution and keep their children and animals closely supervised until the dangerous animals are removed, the city said.